Stator impregnation method

Abstract

Method for impregnating a stator of a rotary electric machine comprising slots, electrical conductors accommodated in the slots, at least two electrical conductors being electrically connected by an electrical connection, the method comprising the following steps: a) heating the stator to a first temperature; b) applying a resin close to the slots of the stator; c) heating the stator to a second temperature; d) applying the resin to the one or more electrical connections of the electrical conductors, application steps b) and d) being achieved through flow of the resin.

1 . A method for impregnating a stator of a rotary electric machine comprising slots, electrical conductors accommodated in the slots, and at least two electrical conductors being electrically connected by an electrical connection, the method comprising the following steps:
 a) heating the stator to a first temperature,   b) applying a resin close to the slots of the stator,   c) heating the stator to a second temperature,   d) applying the resin to the electrical connections of the electrical conductors,   application steps b) and d) being achieved through flow of the resin,   the longitudinal axis of the stator being substantially horizontal or slightly inclined with respect to the horizontal.   
     
     
         2 . A method for impregnating a stator of a rotary electric machine comprising slots, electrical conductors accommodated in the slots, at least two electrical conductors being electrically connected by an electrical connection, the method comprising the following steps:
 a) heating the stator to a first temperature,   b) applying a resin close to the slots of the stator,   c) heating the stator to a second temperature higher than the first temperature,   d) applying the resin to the electrical connection of the electrical conductors,   application steps b) and d) being carried out by flowing of the resin,   step c) of heating to a second temperature beginning before step d) of application to the electrical connections.   
     
     
         3 . The method according to one of the two  claim 1 , comprising the following step:
 c′) heating the stator to a third temperature.   
     
     
         4 . The method according to  claim 1 , the stator being heated by thermal conduction during steps a) and/or c) of heating. 
     
     
         5 . The method according to  claim 1 , step b) of application close to the slots and step d) of application on the electrical connections being carried out by means of at least one nozzle, different nozzles being used to carry out step b) of application in the slots and step d) of application on the electrical connections. 
     
     
         6 . The method according to  claim 5 , further comprising a step of translation of the nozzle(s) which is carried out between step b) of application close to the slots and step d) of application on the electrical connections. 
     
     
         7 . The method according to  claim 5 , step b) of application close to the slots being carried out by means of two nozzles, a first nozzle being located at a first axial end of the stator inside the electrical conductors and a second nozzle being located at the other axial end of the stator outside the electrical conductors, step b) of application close to the slots comprising the following steps:
 b1) applying the resin close to the slots,   b2) moving the nozzles so that the first nozzle is located outside the electrical conductors and the second nozzle is located inside the electrical conductors,   b3) applying the resin close to the slots.   
     
     
         8 . The method according to  claim 1 , the stator being driven in rotation. 
     
     
         9 . The method according to  claim 1 , comprising the following step:
 e) polymerizing the resin deposited on the stator.   
     
     
         10 . The method according to  claim 1 , the first temperature being between 80 and 160° C. 
     
     
         11 . The method according to  claim 1 , the second temperature being between 110 and 190° C. 
     
     
         12 . The method according to  claim 1 , a layer of resin with a thickness of between 0.05 mm and 2 mm being applied to the electrical connections. 
     
     
         13 . The method according to  claim 1 , at least some of the electrical conductors, if not a majority of the electrical conductors, being in pin form, in particular in the form of U-pins or I-pins. 
     
     
         14 . The method according to  claim 1 , the viscosity of the resin at the second temperature being higher than the viscosity of the resin at the first temperature. 
     
     
         15 . The method according to  claim 1 , the resin comprising at least one polyester. 
     
     
         16 . An electrical machine stator impregnated by a method according  claim 1 . 
     
     
         17 . A stator for a rotary electric machine comprising a stator mass comprising slots, electrical conductors accommodated in the slots, at least two electrical conductors being electrically connected defining electrical connections, and comprising a resin comprising at least one polyester filling the slots and covering the electrical connections.